<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <input type="text" />
  <button>按钮</button>
  <script>
    var input = document.querySelector('input')
    var button = document.querySelector('button')

    button.onclick = function() {
      input.disabled = true
      // button.disabled = true

      this.disabled = true

      // this 再普通函数中就指向当前函数调用者   ========== 构造函数。箭头函数特殊
      // console.log(this === button )
    }
  </script>
</body>
</html>